Clamping mechanism



Patented Sept. 14, 1948- UNITED STATES PATENT OFFICE Robert L. McBride,New York, N. Y.

Application January 16, 1946, Serial No. 641,559

immediately prior to and during the fall of the knife.

' Various friction clamping devices have heretofore been used forclamping the pile of paper when the same has been properly positionedinorder to make the desired cut` and also for exerting pressure on theclamping devices when the cut is made. Such `devices have however provenunsatisfactory.,` Some-of them are noisyto an objectionable degree andare subjected to an undue amount of shock and cause piledisturb-` anceson the return stroke of the knife. Furthermore these devices must beoperated at `a limited speed. Also in such devices pressure is lost `dueto oil soaking and `mechanicalV Wear of the parts. Such frictionclamping devices are generally erratic in action resulting in variationsin pressure and in disturbance of the pile of paper;V `Again in suchdevices usually the highest peak of the pressure load is exerted at Vthemoment of cutting which is objectionable.` Also in such devices,excessive pressure adjustment or seizure of friction is likely to` causebreakage of parts of the machine.` 'f

Itis a primary objectyof my invention` to overcome the foregoingobjections and disadvantages. 30

. Another object is to provide improved clampingV means for papercutting machines andthe like that moves at a rapid speed toward the pileof paper and upon engagement therewith exerts a sustained and regulatedpressure thereupon dur- 35 ing the cutting and until the knife leavesthe pile.

Another object is to provide a clamping` device that providesinstantaneous and sensitive control of the pressure. t

Another object is to reduce the drlvingloads.

Another object is to eliminate faulty adjustment or reduce it to aminimum.

Another object is Vto provide clamp actuating mechanism for papercutting machine and the like embodying means for applying pressure to 45such clamp, such means being automatically operative in timed relationto the fall of the knife and upon engagement with the pile of paper;being adapted to exert a sustained and regulated pressure thereuponduring the cutting and until the knife leaves the pile.

Another object is to provide clamping mechanism that is simple inconstruction, inexpensive to manufacture and flexible and positive inaction, y 1 1 4 Claims. (CI. 164-51) Other objects and advantages of myinvention will be apparent from the description thereof to follow takenin connection with the accompanying drawings in which- Fig. 1 is a frontelevational view of a paper cutting machine embodying my inventionIparts vbeing shown in section.

Fig. 2 is a side elevational view thereof.

Fig. 3 is a sectional view on an enlarged scale of the improved clampingapparatus, with the parts in inoperative position.

Fig. 4 is a fragmentary view of the clamping apparatus of Fig. 3 withthe parts in operative position.

Fig. 5 is a sectional view ofthe parts shown in Fig. 4, looking from thefront thereof.

Fig. 6 isa sectional view taken on the plane of the line 6 6 of Fig. 3.I I

Referring now more particularly to the drawings, and especially Fig. 1thereof, the 'paper cutting machine shown therein comprises a frame 5having side members 6 and 'l and a bed or table 8. Reciprocably mountedin slots in the side members is a knife 9, means being providedincluding connecting rods I il and cranks II for impartingreciprocation. The cranks are fastened to the respective ends of shaftI2 which is driven by a motor (not shown).

A clamp I3 is mounted for vertical reciprocal movement to the rear ofthe knife, said clamp being provided with side bars I4 carrying headedstuds I5 at their bottom ends. The clamp is raised to and held inuppermost inoperative position such as shown'in Fig. 1 by means of coilsprings I6 suitably fastened to a bar I1 mounted on the frame.

The present invention is particularly concerned with improved mechanismfor lowering the clamp into engagement with the'pile of paper and forapplying further pressure to the clamp in order to compact and, firmlyhold the pile of paper during the cutting operation. This actuating andpressure applying mechanism includes a rotatable shaft I8 supported inthe top of the frame and lextending on both sides thereof andoperatively connected to and driven by shaft I2 by means of a chain I8',rotatable stub shaft I9 and chain I8. Fastened on each end of the shaftI8 is a cam member 2li provided with a camming groove 2l and a guidingfork 22.

suitably mounted on the frame underneath and substantially in alignmentwith the cam mem-` bers 20 are vertically disposed tubular casings 23.Each casing includes an upper section or cylinder 24, an intermediatesection or cylinder 25 and a means of connection between one of thefluid movable pistons and the clamp member for moving said clamp member.

2. In a paper cutting machine, the combination of a motor, a support fora pile of paper to be cut, a reciprocal knife, mechanism for moving saidknife into engagement with the pile of paper to be cut for cutting thesame including a crank shaft operatively connected to the motor, areciprocal clamp member and hydraulically actuated mechanism for movingsaid clamp into engagement with the pile of papers and subsequentlyexerting a pressure thereupon for compacting the paper and holding samermly during the cutting operation, said hydraulically actuated mechanismincluding a cam member operatively connected to said crank shaft, acasing containing fluid under pressure, a piston in said casingconnected to said cam member and movable thereby, another piston in thecasing operable under the influence of the fluid movable by saidfirst-named piston and a third piston in said casing operativelyconnected to said second-named piston and movable thereby, said lastnamed piston being operatively connected to said clamp member for movingthe same.

`3. In a paper cutting machine, the combination of a motor, a supportfor a pile of paper to be cut, a reciprocal knife, mechanism for movingsaid knife into engagement with the pile of paper for cutting sameincluding a crank shaft operatively connected to the motor, a reciprocalclamp member and hydraulically actuated mechanism for moving said clampinto engagement with the pile of paper and subsequently exerting apressure thereupon for compacting the paper and holding same firmlyduring the cutting operation, said hydraulically actuated mechanismincluding a cam member operatively connected to said crank shaft, atubular casing having upper, intermediate and lower cylinders, saidcylinders containing fluid under pressure, a piston in the uppercylinder operatively connected to the cam member and movable thereby, apiston in the intermediate cylinder movable under the influence of thefluid moved by the piston in the upper cylinder, a piston in the lowercylinder iiexibly connected to the piston in the intermediate cylinderand movable therewith and means of connection between the piston in thelower cylinder and the clamp member for moving the latter.

4. Apparatus as defined in claim 3 characterized by a spring in theintermediate cylinder for cushioning the movement of the clamp member.

ROBERT L. MCBRIDE.

REFERENCES CITED The following references are of record in the

